After confusion and failure, Microsoft realizes it does not need three consumer operating systems.

Microsoft has made it semi-official: Windows RT will go away, eventually. It was a bad idea that never went anywhere, and now it looks like the company is giving up the ghost on this one.

Word comes from Julie Larson-Green, the former Windows group head who is now in charge of Microsoft's devices unit. The Verge reports that during the UBS Global Technology Conference last week, she said:

"We have the Windows Phone OS. We have Windows RT and we have full Windows. We're not going to have three."

The comments come after Terry Myerson, the former Windows Phone head who now runs the entire Windows group, made similar comments during Microsoft's financial analysts meeting in September. "We should have one set of developer APIs on all of our devices. And all of the apps we bring to end users should be available on all of our devices," he told analysts.

Microsoft is working toward a single app store for Windows and Windows Phone, similar to Apple's one-stop App Store for iPhone and iPad. So really, the end is nigh for Windows RT. It never gained much market share due to a lack of apps, which always struck me as odd because RT is ARM-based, just like Windows Phone. How difficult could it be to make Windows Phone 8 apps run on RT?

And Windows Phone is picking up momentum, both the phone and the Store. A Strategy Analytics survey released last week showed developers are warming up to Windows Phone. In a survey of 1,600 mobile app developers, 32% said they plan to support Windows Phone next year. That's double the 16% who said they would support it this past year.

According to Microsoft, the Windows Phone Store has about 190,000 apps with 500 new apps added each day. That's still pitiful compared to the 1 million on iOS and Android, but it's still upward momentum. This growth in apps has resulted in a 181% increase in monthly app revenue from a year ago and a 290% increase in overall app downloads from a year ago.

Windows RT was meant to be the tablet with the long battery life, giving in to the notion that Intel can't make a power-efficient tablet. The Dell Venue 8 Pro proved that notion a lie. In the end, RT was rejected, cost Microsoft $900 million in writedowns, and is likely one of the many reasons Steve Ballmer is headed into retirement.

There is no time table for when RT will be killed off, but don't expect anymore investment in it. It's a dead platform walking.